Character Bio's may have insight on the story though not technically full on spoilers***

Plot
In the near future, a Japanese scientist engineers a powered exoskeleton called "Infinite Stratos" (IS). Possessing technology and combat capabilities far more advanced than any other weapon system, the IS threatens to destabilize the world. Faced with such an overpowering weapon, the nations of the world enact the "Alaska Treaty", which states that IS will never be used for military combat and that existing IS technology must be equally distributed to all nations, to prevent any one nation from dominating the others. The introduction of the IS does, however, have a major effect on society. As IS can only be operated by women, there is a shift in the power balance between men and women, where women now dominate society over men.
------------------------------
Main characters
Ichika Orimura (織斑 一夏 Orimura Ichika?)
Voiced by: Kōki Uchiyama (Japanese), Josh Grelle (English)
The protagonist of Infinite Stratos. He is a first year student at the IS Academy. His older sister, Chifuyu, is a legendary IS pilot who raised him when the siblings' parents abandoned them at a young age. Despite how harshly she treats him, he loves his sister dearly. As the first male IS pilot, his new reputation has made him somewhat famous as many scientists and engineers would like to study him. He is oblivious to the fact that some of his female friends have feelings for him. He pilots the Byakushiki (白式?, lit. White Expressions) IS,[2] a prototype, one of only two developed 4th-generation IS focused on short-range melee attacks. He also possesses Chifuyu's Yukihira Type 2 (雪片弐型 Yukihira Nigata?), upgraded from the version used by his sister; and Core Number 001, the very first IS core. Later it is revealed that he also has a twin sister, Madoka, who harbors a grudge on Chifuyu.
Later on, Byakushiki undergoes Second Shift shortly after Houki Shinonono acquires her personal unit, Akatsubaki. In the resulting Second Shift form, named Byakushiki Setsura (白式雪羅?), it is equipped with a multi-function unit Setsura (雪羅?), which has: a high-caliber charged particle cannon, an energy claw for close-quarters combat, and an energy shield with the One-Off ability. In its Second Shift, Byakushiki also gains an increase in mobility through the addition of 4 large wing thrusters, enabling it to execute Double Ignition Boost.[volume & issue needed] In this Second Shift form, it is the best IS ever made along with Houki's Akatsubaki.

Houki Shinonono (篠ノ之 箒 Shinonono Hōki?)
Voiced by: Yōko Hikasa (Japanese), Monica Rial (English)
Houki is a first-year student at the IS Academy and Ichika Orimura's childhood friend, though they have not seen each other for six years.[3] She has a very long ponytail.[4] Her place of residence is home to a kendo dojo, which led to her early interest in kendo. Houki even competes in kendo competitions at a national level, and was the winner of the national tournament that was hosted one year before the story of Infinite Stratos began.[5] She is part of the kendo club at the IS academy. Her older sister, Tabane Shinonono, is the creator of the IS, though their relationship is strained. Six years ago, Ichika agreed to become her boyfriend if she could win the national kendo tournament of their grade. However, the day of the tournament is also the day the IS was introduced to the world. Due to the familal links to Tabane, Houki's family is placed under government protection and Houki is forced to withdraw from the kendo tournament. Since that incident, Houki resents her sister for moving her away from Ichika and abandoning their family.Despite not seeing him for a long time, Houki still harbors strong feelings for Ichika, as her continuing practice of kendo was her only link to him. She was his initial roommate before the arrivals of Charlotte Dunois and Sarashiki Tatenashi, and tends to get jealous when other girls are around him. Originally not possessing a personal IS, in Volume 3 she receives and pilots the Akatsubaki (紅椿?, lit. Red Camellia) IS, one of only two developed 4th generation IS and a short-range melee-class IS, armed with twin katana named Amatsuki (雨月?, "Rainy Moon") and Karaware (空裂?, "Cracked Sky"). The Akatsubaki has a One-Off ability called Kenran Butō (絢爛舞踏?, "Magnificent Dance"), which allows Houki to replenish both her own and other IS's energy when she comes in contact with them. However, because she is still unskilled as a pilot and her compatibility with the IS is only at grade C, she is still considered to be on the same level of the other girls. As of Volume 7, her compatibility has risen to grade S.
------------------------------

There's a description and Character Bio's for 2 of the main characters.

Let me know what you think. Stay tuned for another anime recommendation next week !